Controlling mechanisms for the tools in a log debarking machine



BRUNDELL HANISMS FOR T DEBARKING ETAL 3,196,912

HE TOOLS IN A LOG MACHINE 3 Sheets-Sheet 1 July 27, 1965 P. G.CONTROLLING MEG Filed April 25, 1962 y 27, 1965 P. a. BRUNDELL ETALCONTROLLING MECHANISMS FOR THE TOOLS IN A LOG DEBARKING MACHINE FiledApril 23, 19 62 3 Sheets-Sheet 2 July 27, 1965 P. 5. BRUNDELL ETAL 3, 2

CONTROLLING MECHANISMS FOR THE TOOLS IN ALOG DEBARKING momma Filed April2:5, 1962 s Sheets-Sheet :s

United States Patent 3,196,912 CUNTRQLLING MECHANEMS FGR THE TGULS IN AlLQG DEBARKHNG MACHINE Per Gunner Brundell, Tolfiors, Ga le, andKarl-Erik Arnold .l'onsson, Gayle, Sweden, assignors to Soderharnnsgerlstader Ali, Soderhamn, Sweden, a corporation of we en rues Apr. 23,1962, her. No. 189,467 Claims priority, application fivveden, May It),H61, 4,?41/ 61 3 Claims. (Cl. 144-208) The invention relates to adebarking machine of the type in which an annular rotor journalled in astator has a central opening through which logs are to be passed. Therotor carriers bark-removing tools mounted to swing towards and awayfrom the center of the opening in a plane substantially normal to theaxis of the rotor, and resilient means are provided to cause the toolsto swing inwardly to engage resiliently the surface of a log fed throughthe rotor.

In the operation of such a machine it may sometimes, for some reason orother, be desired that the advance of a log introduced in the rotor istemporarily stopped, e.g. for cutting off the log. If, during suchstoppage, the machine is allowed to continue its operation there will bea risk that the tools cut or turn a more or less deep annular groove inthe surface of the log.

The object of the invention is to obviate this drawback and for thatpurpose the invention provides a device by means of which the tools canbe retained in inoperative position during the rotation of the rotor.Thus, the rotor has mounted thereon retaining means adapted, whenoperated, to prevent each tool from moving in wards from a positionreached, and a stationary release member is then adapted to be actuatedmanually to put all of said retaining means into operation at any momentduring a debarking operation. In this way, the tools will be retained ona circle having its center in the axis of the rotor and circumscribingthe outermost point of a log surface contacted by the tools. It may benoted that said retaining means are not adapted to displace the toolsradially outwards against the action of rather heavy resilient means butonly serve to prevent the tools from a further inward movement whichmight cause a continued peeling of the log surface.

In a suitable embodiment, each retainin mean consists of a fluidpressure operated cylinder provided with a piston rod and connected to apressure fluid accumulator by means of a conduit containing a normallyclosed solenoid valve which is adapted to be opened on actuation of astationary switch inserted in the circuit of said solenoid. The openingof the valve causes the piston rod to move outwards, and thus eithersaid rod or the cylinder may serve as a retaining member, Anothermechanism is then provided to automatically prevent the return of saidmember from its retaining position. The locking mechanism may consist ofa catch operated by means of an electromagnet in some known way, but ina preferred embodiment said conduit between the accumulator and thecylinder may also contain a non-return valve closing onto theaccumulator and thus preventing the baclzflow of the pressure fluid'when the retaining member is subjected to the pressure of the toolspring. To permit the return of the pressure fluid to the accumulatorand thereby the release of the retaining member it is, however,necessary in this case to provide a second conduit containing a normallyopen solenoid valve which is adapted to be closed when the solenoidvalve in the first conduit i opened.

The invention will be described more in detail with reference to theaccompanying drawing which show two different embodiments.

In the drawings,

FIGURE 1 shows the location of retaining mechanisms on the rear side ofthe fore end Wall of a debarking rotor in which belts or bands of rubberare provided to swing the tools.

FIGURE 2 shows a more detailed view of a portion of the same wall andone of the retaining mechanism on a larger scale.

FIGURES 3 and 3a show another embodiment applied on a debarking toolactuated by other resilient means.

FIGURE 4 is a cross-sectional view illustrating the stator and rotorrelationship.

The rotor shown in FIGS. 1 and 2 may be of the type described in the US.Patent No. 2,857,945. Three debarking tools 3 are provided before thefore end walls of the rotor equally spaced around the periphery. Thetools 3 are secured to pivots 4 journalled in said wall 5. On the rearside of the wall 5 (shown in FIGS. 1 and 2) each pivot 4 has securedthereto a crank carrying a pin 7 directed axially rearwards. Each pin '7is by means of one or more elastic belts or hands 8 of rubber coupled toa pin 9 inserted in the wall 5 at a distance from the pivot 4 of thepertaining crank. As apparent, the arrangement is such that the rubberbands strive to swing the tools 3 inwards towards the axis of the rotor.Shortly before the free ends of the tools meet at said axis or centerline, however, the inward swinging movements are stopped by stationaryabutments. For that purpose, fins 10 projecting axially from the cranks6 are arranged to abut rubber pads 11 carried by angle irons 11a whichare secured to the wall 5 inside the rubber belts 8. The constructiondescribed hitherto is known previously.

According to the invention, one retaining mechanism is provided for eachof the debarking tools 3 and therefore only one of these mechanisms Willbe described below with reference to FIG. 2. A hydraulic cylinder 12having a piston rod 13 is secured to the rotor wall 5. The piston rodand adjacent end of the cylinder extend through a transverse opening inthe limit stop 11, 11a in such a way that the piston rod 13 in its fullyretracted position has it end located in the same plane as the stopsurface of the pad 11 that faces the tin it The rear end of the cylinder12 is by means of two conduits i4, 15 connected to the fluid chamber ofa pressure fluid accumulator 16. According to a known construction, theaccumulator also includes a chamber separated from the fluid chamber bya flexible diaphragm and filled with gas under pressure whereby arequired pressure in the closed system can be maintained. The conduit 14contains two valves: a nonreturn valve 1'7 opening towards theaccumulator and a solenoid valve lit which is open when the circuitthrough the solenoid is open. Also the conduit 15 contains two valves: anon-return Valve 19 opening towards the cylinder l2 and a solenoid valve2! which is closed when the circuit through the solenoid is open. Inother words, in the illustrated arrangement fluid can flow fromaccumulator re past valve 29 when it is open through conduit 15 and pastcheck or non-return valve 15", in the direction of arrow X, towardcylinder 12 but cannot flow back past the valve 719. On the other hand,fluid can fiow from cylinder 12 through conduit 14 past non-return valve37, in the direction of arrow Y, and past 13 when it is open toaccumulator 16 but it cannot flow in the reverse direction past valve 17toward the cylinder 12.

A cylindrical rotor wall 21 indicated diagrammatically in FIG. 2 andextending along the outer periphery of the end wall 5 carries on itsexterior surface two peripheral rails 22 and 23, one of which 23 iselectrically insulated. Brushes 24 and 25, respectively, are mounted ona stator 35a, in contact with said rails 22, 23. Bearings 36 journal therotor relative to the stator, see FIG. 4-. The brush 24 is connected toground by means of a conductor 26, and the brush 25 is connected to asource of current by means of a conductor 27 containing a normally openswitch 23. The solenoids of the valves lid, 20 are by means ofconductors 29, 3t 31 connected in series between the two currentcarrying rails 22, 23.

It may be assumed that in an initial position, not shown, the tools 3engage the surface of a log (32 in FIG. 1), the advance of which throughthe rotor it stopped, To prevent a continued peeling of the annular logsection opposite to the tools, the switch 28 is now actuated so that thesolenoid valve 18 in the conduit 14 is closed and the solenoid valve Ztiin the conduit is opened, and thereby pressure fluid is supplied to thecylinder 12 through the non-return valve 19. This causes the piston rod13 to move outwardly to hit the fin it} of the crank 6 irrespective ofthe actual position of the tool 3. The pressure in the cylinder 12 isquite insufficient to cause any displacement of the tool outwards fromthe log surface against the action of the strong rubber spring 8, but onthe other hand the tool has no possibility to swing in oppositedirection, is. inwards, as the non-return valve 19 closes the conduit15, as soon as the piston rod is actuated by the spring 8 and therebycauses a higher pressure in the cylinder 12 than in the accumulator 16.As long as the switch 28 is closed and the valve is open, the piston rod13 follows the arm 6, if the log, which often i not quite round, shouldcause some further outward movement of the tool. As already mentioned,all retaining or blocking mechanisi is that is, position limiting means,are of the same design, and they are all connected to the current railsin the same way to be put into operation simultaneously on actuation ofthe switch 28.

In FIG. 1, it has been assumed that the rotor has rotated about half aturn after the retaining mechanisms have been put into operation. One ofthe tools, designated by A, has just reached the log surface portion 33located at the greatest distance from the center of rotation. The tool Bbefore the tool A has been blocked or limited in the position reachedwhen passing the surface portion 33, whereas the tool C behind the toolA is still in engagement with a successively rising log surface. After arotation of at most one turn all tools have been positioned with theiredges disposed on a circle 34 having its center on the axis of the rotorand circumscribing the most protruding surface portion 33, whereby acontinued debarking is excluded.

When the interrupted advance of the log is again to be resumed, and thedebarking is thus to be continued, the switch 28 is returned to itsnormal open position, whereby the solenoid valve 20 is closed and thesolenoid valve 18 is instead opened. Now, the piston rod 13 is forcedback by the spring 8, as the liquid has free passage to the accumulator16 through the conduit 14. The non-return valve 1'7 prevents a flow inopposite direction, when the action of the spring against the piston rod13 is temporarily relieved.

In the embodiment in FIG. 3, the crank 35 on the pivot 4- of the tool 3is hinged to the piston rod 36 of a piston 37 in a cylinder 33. Acylinder space behind the piston 37 is by means of a conduit 39connected to another cylinder lt) containing a piston 41. The spaceformed between the two pistons 37 and 41 is filled with liquid actuatedby the pressure of a heavy helical spring 42 mounted on the rear side ofthe piston 41. The conduit 39 contains a normally open solenoid valve4-3 adapted to be controlled by a stationary switch 28 arranged in acircuit including the components similar to those illustrated withrespect to the form shown in PEG. 2. A branch conduit 44 connected tothe conduit 39 on both sides of the valve 43 contains a non-return valve45 opening toward the cylinder 40. When the valve 4-3 is open, the twocylinders 38 and will evidently serve the same purpose as the rubberspring 8, i.e. to move the tool resiliently onto the log. ()n the otherhand, when the vazve 43 is closed, the device will function as aretaining mechanism in the same Way as the embodiment first described,in that the non-return valve 45 retains the tool 3 on the circlecircumscribing the outermost portion of the log.

FIG. 3a shows a modified embodiment, in that the piston 41 and thespring 42 are replaced by an elastic bladder 46 connected to a source ofcompressed air, not shown.

In both the embodiments described, the electrical control circuit mayvery well be replaced by control means operating mechanically,hydraulically or pneumatically.

What we claim is:

l. A debarking machine of the hollow-head type includin a stator, arotor journalled in the stator having a central opening through whichlogs to be debarked are passed, a plurality of shafts journalled axiallyin said rotor, a bark-removing tool carried by the rotor and mounted formovement toward and away from the axis of the opening, a crank fixed toeach shaft, fixed members on the rotor respectively spaced from eachcrank in the direction of movement thereof, resilient means con nectedbetween each crank and associated fixed member to cause the associatedtool to swing inwardly to resiliently engage the surface of a log fedthrough the rotor, hydraulic pressure operated cylinders mounted on therotor and a movable piston in each cylinder adapted, when moved, toengage one crank in opposition to the action of said resilient means, ahydraulic pressure accumulator, a supply conduit from the accumulator tothe cylinder including a normally-closed solenoid operated valve and anon-return valve opening towards the cylinder, a return conduit from thecylinder to the accumulator including a normally-open solenoid operatedvalve and a non-return valve opening towards the accumulator and astationary switch connected in the circuit with the solenoids andadapted, when operated, to reverse said solenoid valves, whereby thepistons of the cylinders are operated to serve as blocking members.

2. A dcbarking machine of the hollow-head type including a stator, arotor journalled in the stator having a central opening through whichlogs to be debarked are passed, a plurality of shafts journalled axiallyin said rotor, a bark-removing tool carried by each shaft and mountedfor movement toward and away from the axis of the opening, a crank fixedto each shaft, means connected with each crank to cause the tools toswing inwardly to engage the surface of a log fed through the rotor todebark the same, hydraulic pressure operated cylinders mounted on therotor and a movable piston in each cylinder for engaging one crank inopposition to the action of said means, a hydraulic pressureaccumulator, a supply conduit from the accumulator to the cylinderincluding a normally-closed solenoid operated valve and a non-returnvalve opening towards the cylinder, a return conduit from the cylinderto the accumulator including a normally-open solenoid operated valve anda nonreturn valve opening towards the accumulator and a stationaryswitch connected in the circuit with the solenoids and adapted, whenoperated, to reverse said solenoid valves, whereby the pistons of thecylinders are operated to serve as blocking members.

3. A debarking machine comprising a stator, an annular rotor journalledin the stator and having a central opening through which logs are to bepassed, a plurality of shafts journalled axially in the rotor, equallyspaced around said central opening and each carrying a barkremoving tooladapted for swinging movement towards and away from the center of theopening in a plane substantially normal to the axis of the rotor, acrank fixed to each shaft, a hydraulic cylinder and piston unit for eachcrank, each piston having a rod connected to the associ ated crank, 21second hydraulic vessel, conduit means connecting the cylinder spaceremote from the piston rod to said second vessel, means generating ahydraulic pres- E5 sure in said second vessel, a normally open solenoidvalve in said conduit means, a by-pass conduit connected to said firstconduit means on opposite sides of said valve, a non-return valve in oneportion of said by-pass conduit opening towards said second vessel, anda manually operated stationary switch connected to close all solenoidvalves upon manual operation so as to position the tools with their tipsheld lying on the circumference of a circle having its center at theaxis of the rotor and circumscribing the outermost point of a logsurface contacted by the tools.

References Cited by the Examiner UNITED STATES PATENTS 2,798,519 7/57Hansel 144208.5 5 2,802,495 8/57 Nicholson 144208.5 2,925,107 2/60Fitzwater 144208.5 3,053,294 9/62 Andersson 144-208.5

LESTER M. SWINGLE, Primary Examiner.

10 EARL EMSHWILLER, WILLIAM W. DYER, 111.,

Examiners.

1. A DEBARKING MACHINE OF THE HOLLOW-HEAD TYPE INCLUDING A STATOR, AROTOR JOURNALLED IN THE STATOR HAVING A CENTRAL OPENING THROUGH WHICHLOGS TO BE DEBARKED ARE PASSED, A PLURALITY OF SHAFTS JOURNALLED AXIALLYIN SAID ROTOR, A BARK-REMOVING TOOL CARRIED BY THE ROTOR AND MOUNTED FORMOVEMENT TOWARD AND AWAY FROM THE AXIS OF THE OPENING, A CRANK FIXED TOEACH SHAFT, FIXED MEMBERS ON THE ROTOR RESPECTIVELY SPACED FROM EACHCRANK IN THE DIRECTION OF MOVEMENT THEREOF, RESILIENT MEANS CONNECTEDBETWEEN EACH CRANK AND ASSOCIATED FIXED MEMBER TO CAUSE THE ASSOCIATEDTOOL TO SWING INWARDLY TO RESILIENTLY ENGAGE THE SURFACE OF A LOG FEDTHROUGH THE ROTOR, HYDRAULIC PRESSURE OPERATED CYLINDERS MOUNTED ON THEROTOR AND A MOVABLE PISTON IN EACH CYLINDER ADAPTED, WHEN MOVED, TOENGAGE ONE CRANK IN OPPOSITION TO THE ACTION OF SAID RESILIENT MEANS, AHYDRAULIC PRESSURE ACCUMULATOR, A SUPPLYING CONDUIT FROM THE ACCUMULATORTO THE CYLINDER INCLUDING A NORMALLY-CLOSED SOLENOID OPERATED VALVE ANDA NON-RETURN VALVE OPENING TOWARDS THE CYLINDER, A RETURN CONDUIT FROMTHE CYLINDER TO THE ACCUMULATOR INCLUDING A NORMALLY-OPEN SOLENOIDOPERATED VALVE AND A NON-RETURN VALVE OPENING TOWARDS THE ACCUMULATORAND A STATIONARY SWITCH CONNECTED IN THE CIRCUIT WITH THE SOLENOID ANDADAPTED, WHEN OPERATED, TO REVERSE SAID SOLENOID VALVES, WHEREBY THEPISTONS OF THE CYLINDERS ARE OPERATED TO SERVE AS BLOCKING MEMBERS.